Well i've come across something interesting tonight. I fear I may have killed my second magnaflow highflow cat. I was running the truck a little harder than usual when an oh so familiar smell hit my nose. I instantly thought to myself... damn that smells like a bad cat (sulfur smell suddenly inside the cab like the 94109 cat would after I got on the pedal). Sure enough 15 minutes down the road I look at my cluster and there it is, the good ole CEL. So I debate with my brother and ask how much he wants to bet it is either a P0420 code, or a P0601 code since I seem to have good luck in killing computers too. Sure enough when I got back home and it was the catalyst inefficency code (0420). So now what will actually fix my problem? I have no money at the moment so I pulled the non-foulers I had downstairs out tonight (from a different project) and drilled the one BUT... I am afraid it won't fit. (see picture)



But I am curious to ask what would actually "fix" my problem since I can't seem to keep cats alive? Oh, also o2's were changed a year ago or so with NTK sensors. For those who didn't know I cut the stock cat out for the highflow 94109 because everyone was doing it. Then when it threw a cel I swapped to the 99 series cat suggested by aim4squirrels. Edit, I've also considered the fastman o2 simm, but again im more curious as to why the cats fail on me.

 

If i'm not mistaken your problem would be with the pre cat censor and not the back,you may have room for anti foulers on the pre cat

 

Well... after holding everything in my hand and studying the parts I came up with something a little different. Since I went under the truck this morning and actually looked... I know for sure I can't fit two non-foulers together as I suspected last night. Also after drilling the first non fouler out... I was a bit puzzled. I told myself damn.. that is a lot of extra room in the front. (see pic)



This is how it is normally done using the fitting I drilled out.



And... this is how I decided to drill the second one out. Again I don't have the room for two... so why wouldn't this work?



And here it is screwed into a o2 bung (the same that was welded into my pipe... I have 4 extras... any takers jk) Bung is welded even in the pipe (in and out of pipe).



And here is how an o2 normally sits in the bung on my truck.



All in all.. I guess we will see what happens. Hopefully this does the trick. Yeah I think this way will give more exhaust to the o2 sensor using one non fouler instead of two... but as long as it shows enough of a difference between the two, that is all that matters... right? Only time will tell...

 

Are you running a non fouler on the front O2 sensor? That's a huge no no! That sensor has to know what the real A/F ratio is in order to tune the engine properly. Only the rear O2 gets a non fouler. If you are running a 99XXX series, you don't need or want the non fouler. The ct will function correctly.

There are only 2 things that will kill a cat, excessive oil and excessive heat. If the non fouler is on the front O2, I'd guess excessive heat as the engine is running too lean and too hot. Other things contributing to too much (or too little) cylinder heat are:

Retarded spark - will cause glowing headers or manifolds
Weak spark - too much unburnt fuel getting to cat to be burnt up - check coil, cap rotor, wires and plugs
Leaky injector - too much raw gas in cylinder, actually can cool cylinder too much and Cause carbon build up- use mechanics stethoscope and listen to each injector click when it fires.
Too cold of plug - inefficient burn and build up in cylinders and exhaust. If you are running colder plugs just to run them, lose them and go with stock temp plugs. Only swap plugs for colder if you are actually pinging, otherwise it's a waste of fuel.
An exhaust leak prior to the O2 sensor will allow too much oxygen into the exhaust gas pulse and cause the O2 sensor to read too lean and put too much fuel into the equation. This is usually perceived as a loss in power especially when you first blip the pedal to go. Check your header bolts and collector bolts and make sure they are tight.

If the truck is burning oil excessively, check these things:

Faulty PCV valve- stays open and lets oil back into the intake. Will look like a plenum leak in the intake.
Plenum - oil in down the intake, obvious problem; millions of posts.
Valve stem seal - particularly bad carboned cylinder and hissing at the valve on a leak down test
Oil control ring on the piston - run some MCCC or seafoam and sell truck immediately. Probably will hiss at the oil dipstick tube on a leak down test, but not at the oil fill cap.

Those are some ideas to get you running correctly. Something's not right in your engine mixture to be killing cat's the way you have been.

 

No, I am not running a non-fouler on the front nor did I mentioned running one in the front. The first picture of the thread was a picture of the rear o2 sensor. I am running the 99xxx cat... but like i said in the first post I smelled the sulfer smell that I used to smell with the old 94109 cat and soon after the check engine light came on with p0420.


ok, noted. Again the non-fouler is not on the front. I just installed this on the rear this afternoon. The truck is also not running hot temperature wise. It is where it always has been. (in the middle of the first and middle mark)

Headers don't glow

Tune-up done two years ago approx 20k mi. summit cap & rotor, mopar perf wires, stock temp champion plugs. Will note that there is no miss-firing.

Will see what I can do on that one.

Running stock champion plugs

I will check my collectors and order those metal gaskets.

PCV valve is good. I am pretty sure my valve stem seals are going. I have had puffs of smoke come out on start up before, but it does it... and doesn't do it again for a long time (months). I will try some seafoam some weekend when I get bored should be fun.

 

To update the thread, I purchased the edelbrock collector gaskets (the only ones i could find) and they don't work with pacesetter headers. I tried to re-work one with my dremel and that still didn't work, so there went $26 down the tube (slaps knee). While the pipes were down, I took a piece of sand paper around the inside of the y-pipe lightly at the lip. I did find that my collector bolts were loose so I re-bolted them back up nice and tight and made sure they were correctly seated. Followed with an oil change, and then threw 1/2 seafoam through the brake booster line, and rest in gas tank. Always love a good smoke show.